Air-cooled gun barrel



Nov. 28, 1944. N. L. vmsou- AIR COOLED GUN BARREL Filed NOV. 18, 1942 Patented Nov. 28, 1944 UNITED STATES PATENT OFFi-CE AIR-'GOOLED GUN'BARREL Neal 1.. Vinson, Mill yalley, -Calif. fipplication November 18, I942,-Serial No. 465,969 3 Claims. (o1.-.s9-14.1)

(Granted under the act f"March '3, -1883, as

amended April 30, 1928; 370 0. G.

The invention described herein'may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to devices for cooling the barrels of automatic firing weapons, more particularly, of the air cooled type. The object of the invention is to provide an air cooling device for,

such weapons which will attain efiicient barrel cooling by reason of an increased flow of air compared with devices heretofore known. Allied with this object, the improved device is simple, inexpensive to construct and to apply to the gun barrel, and is sturdy for the type of service such equipment receives under field conditions. For the attainment of these and such other objects as may appear or be pointed out, I have shown an embodiment of my invention in the accompanying drawing, wherein:

Fig. 1 is a sectional elevation of the muzzle end of a gun barrel with the improved cooling device in place.

Figs. 2, 3 and 4 are cross sectional views taken respectively on lines 2--2, 3-3 and 4-4 of Fig. 1, and

Fig. 5 is a section through one of the supporting fins, taken on line 5-5 of Fig. 1.

The muzzle end of a barrel I of an automatic (rapid) firing weapon is shown in Fig. 1 together with its usual jacket cylinder 2 separated from the barrel by a considerable distance (when compared with the barrel bore) and provided with a plurality of air ports 3.

The improved cooling device of this invention is applied to the end of the jacket 2, as by means of machine bolts (shown) or other fastening means, and comprises a short length of tubular material in the form of a sleeve 10. In the interior of short sleeve It (more exactly within the annular space between short sleeve in and the central bullet passageway are a number of ring members-three being shown in Fig. 1 and designated II, 12 and I3, which are secured to the inside surface of sleeve Ill by radial fins designated, respectively, Ha, [2a and l3a.

The ring member nearest the muzzle H is the smallest diameter, the diameter of the members increasing in diameter towards the mouth of the sleeve H], the member next to the exit l3 having the greatest diameter. The ring members I I, l2, 13 function in the manner of aspirating rings which, as the expanding flame sheet issues from the barrel muzzle and is confined in its expansion by the expanding series of aspiration rings ll,

i2, l3, create a pronounced suction at, and beyond, the gun muzzle which causes a flow of air along the barrel, the air entering the annular space between the barrel and jacket 2 through the air ports 3. As clearly seen in Fig. 1, the exit mouth (right, as viewed in that figure) of an aspirator ring is in juxtaposition to the entrance mouth (left) of the succeeding ring and is of smaller diameter than the entrance mouth diameter of the succeeding ring. Thus, each pair of ring members, ll, 12 and l2, l3, additionally function in the manner of venturi, by creating points of low pressure (at regions designated A and B, Fig. 1).

The radial fins Ha, Ha, [3a (which may have streamlined edges, as shown in Fig. 5) are preferably secured to the sleeve ID at different angular positions to present a helical path to the flow of air in the annular space between the aspirator rings and the sleeve. In addition, the fins (not shown) which support the jacket 2 from the barrel I may also be arranged in a similar helical manner.

The exit mouth of sleeve l0 may be provided with a double-bevel portion M, which coacting with the exit end (right) of the last aspirator ring 13, causes a point (C) of low pressure by venturi action and thus adds to the aspirating effect of the rings.

I claim:

1. A cooling device for fire arms having a perforated jacket surrounding the barrel and spaced therefrom to,provide an annular space for the passage of cooling air, comprising in combination, a sleeve secured to the end of the jacket and extending beyond the gun muzzle, a plurality of closely associated axially aligned open end separate tubular members centrally supported in the sleeve, said members spaced from the sleeve and increasing in diameter from the innermost to the outermost one, the innermost member being closely adjacent the muzzle of the gun when in battery position and having a gas entrance opening of approximately the same diameter as the bore of the gun to create a strong initial suction at said entrance opening, the gas exit opening of said member being greatly in excess of said entrance opening but substantially smaller than the gas entrance opening of the succeeding members whereby a succession of unrestricted gas exit passages are formed through all of the members to assure the continuous and increasing expansion of the gases from the innermost member through all the members, said succeeding memand extending beyond the gun muzzle, an inner,-

outer and intermediate member closely associated and axially aligned, said members comprising hollow open end tubes centrally supported in the sleeve, the gas entrance opening of the innermost member being approximately the diameter of the gun bore, and its exit opening being greatly in excess of said entrance opening and substantially "less than the gas entrance opening of the intermediate member, the gas exit opening of the intermediate member being of less diameter than the gas entrance opening of the outer member, whereby the gas in passing through said members increasingly and uniformly expands from the inner member to and through the said outer member and air suction openings are formed between the members.

3. The invention of claim 1 characterized in that there is provided at the mouth of the sleeve adjacent the exit opening of the outer member, an internal annular rib to form a restriction between the outer end of the outer member and the sleeve.

' NEAL L. VINSON. 

